I have a 2015 Prius with 76k miles. I bought it from the original owner at 72k miles. All required maintenace was done at the Toyota Dealership. Last winter I had a loud rattle for 5 seconds. Never happened again and no codes were set. Is that the dampener between the gas engine and electric motor making the loud noise? Is that a definitive a sign of a head gasket leak or are there other possible causes? The recommened method of checking the head gasket is to pressurize the cooling system and put a camera in the cylinders and look for a very slow drip from the head gaket. I can't do it myself and can't find anyone in my area that will use the recommened method. I feel that it would be thowing money away and not getting an accurate diagnosis.
Yes, the noise (rattle) is coming from the damper plate when misfires occur in the engine. Why have you created a new thread rather than continuing in the "Death Rattle" thread ( https://priuschat.com/index.php?posts/3540396) that you started already? If you only had the death rattle (misfires) once, it was caused by condensation being sucked into the engine from the intake manifold! You do not have a bad head gasket! I will request that a moderator merge this thread into the other thread that you created.
My other posts for some reason would never show correctly on my computer. I contacted the moderator and had the posts removed.
Your "Death Rattle" thread has not been deleted. Click on the link I provided. I repeat. YOU DO NOT HAVE A BAD HEAD GASKET. Just drive your car!
I can't see the other two posts on my compter. Iv'e been posting on Prius Chat for years and never had a posting problem untill my death rattle posts.
i don't think it is the head gasket either. these engines do randomly misfire on cold startup from time to time based on several factors. one thing to avoid is starting it and shutting down before it reaches full operating temperture and shuts down the engine itself. you can help reduce warmup time if necessary by lowering the cabin temp setting
Thank you for your reply. My rattle happened at start up, in the garage in the morning. I didn't shut the engin off and the rattle went away in about 5 seconds. I really appeciate your help.
Repeating from the other thread, if it happens again then look into a borescope inspection. Most conventional non-hybrids never exhibit symptoms at this stage. Most local mechanics know how to deal with those cars. Generally conventional car owners drive for months with a slight hg leak before it progresses to an advanced hg leak. Those cars then exhibit traditional coolant loss, combustion gasses in the coolant, white smoke out the exhaust or a blown engine. Third gen Prius engines with a spring loaded damper and two powerful electric motors which can and do have an unusual early hg symptom, eg occasional severe rattling that quickly goes away. "Occasional" means now and then - not just once. A Toyota dealer knows Prius hg symptoms but their service model is to witness the symptoms before recommending a rebuilt engine. Both of which are not helpful for your singular, one time problem. Assuming it is really just once, months ago. A shop that specializes in hybrids will do a borescope inspection for a fee. The diagnostic fee may be as high as a dealer but is recommended as they will offer repair options that a dealer will not. You may have to drive across town and the shop may be small. Best advice - don't worry about it until it happens again. If you can't stop worrying then sell or trade it while it's still worth something.
Thats great infomation. Thank you for your insight. Ive heard alot of Gen 3 Prius owners say they have only experienced the rattle during low weather temps. Any input from people who have experienced that symptom would be appreciated.
Hi bisco. I bought my 2015 Prius based on The Car Care Nut YouTube channel. He said the 2015 Prius had the piston ring and head gasket problems resolved. But when I called the Toyota dealer parts dept. they said the 2015 Prius had the same head gasket as the 2010 Prius. The 2015 Prius head gasket did have a different part number than the 2010 Prius head gasket. But to him it looked like the same head gasket.
The 2015 has better piston and rings than a 2010-2013 including some 2014s. Toyota also revised the intake manifold, egr valve and control logic in the engine ecu. There was a revised head gasket with more of the black sealing layer but it's not clear when a production change included them in new vehicles. Your 2015 may have the manifold and egr valve but all gen3s except the 2017 Prius v have revised engine ecu software available. There were significant engine and cooling system changes made in gen4 engines which did solve the gen3 hg problems in cars that had not overheated. Gen4 Prii still command a premium price. They have an exhaust heat recirculating system that have been known to leak coolant, overheat and blow head gaskets. Primarily in the first two years of gen4s. Drivers often don't recognize the high temperature alert's importance and keep driving to their destinations.
Thank you rjparker. Thats some great information. I know I've seen an image of the head gasket you mentioned. I thought the Toyota parts department guy would have pulled that newer head gasket up in his system. But he didn't. He said said it was the same head gasket through 2015, although the 2015 head gasket did have a different part number. That's very confusing to me. My Prius did get the engine ecu software update done at the dealer. It's in the service records. I've seen a Youtube video of the leaking exhaust heat recirculating system. When the coolant system was pressurized, coolant started flowing into the the catalytic converter. My main source of YouTube videos are posted on The Car Care Nut Channel.
